Field of Endeavor
The invention refers to a method for the reliable, low-NOx-emission operation of a stationary gas turbine plant with hydrogen-rich fuel gas, and also to a gas turbine plant with a device for carrying out the method.
Brief Description of the Related Art
The research and development of the combustion of hydrogen or hydrogen-rich fuels in gas turbines is essentially driven forward by two factors.
On the one hand, there is a global interest in reducing the emission of greenhouse gases, especially of CO2. One possibility for this is the changeover from conventional fossil fuels to a hydrogen-based energy supply. In this case, this can, first of all, still be based on conventional fossil raw materials with hydrogen synthesis and CO2 bonding.
On the other hand, the limited natural gas reserves lead to considerations of using synthetically processed gaseous fuels alternatively to, or in combination with, the combustion of conventional types of fuel. These synthetically processed gaseous fuels, as are found for example in an IGCC (Integrated Gasification Combined Cycle), frequently contain high hydrogen concentrations.
The combustion of hydrogen in conventional combustion systems of gas turbines leads to technical problems, as is known, such as increased NOx emissions and flashback, on account of the high flame velocity and short ignition delay times of the hydrogen.
As a countermeasure, in addition to the simple reduction of the operating values, the possibility of diluting the hydrogen-rich fuel with N2 or other inert gases, and especially different concepts for the dilution of the combustion air or of the fuel gas with steam, are known. In this case, steam is injected, or water is injected for evaporation in the air passage or in the fuel system.
So, for example, EP0731255 describes a gas turbine in which superheated steam and/or saturated steam, after superheating in a heat exchanger, is injected into the combustion chamber. As a further step, as a result of which the efficiency of the power plant is improved, EP0899438 outlines the use of water vapor for cooling different components before the steam is introduced into the combustion chamber.
According to EP1659277, water or water vapor is injected into the flow of the combustion air which is compressed by the compressor, before entry into the combustion chamber, in order to reduce the NOx emissions.
DE19900026 describes a way in which water or water vapor is advantageously already injected into the compressor and therefore the compression work and the compressor exit temperature is reduced.
EP1065347 describes a method for the saturation of fuel gas with water and superheating the resulting fuel gas-steam mixture before this is introduced into the combustion chamber of a gas turbine power plant.